If you’ve ever seen “&:” and wondered what it does, then here’s a quick overview of what this little shortcut can do. I’ve provided a simple example without going too deep into the details. (but see the links at the end of the post for more information)
For our example we’ll take an array of words and return a new array where each word has been converted to uppercase.
#!/usr/bin/env ruby
tubbies = ["Dipsy", "Lala", "Po", "Tinky Winky"]
# using map and a block
tubbies_upcased = tubbies.map { |tubby| tubby.upcase }
p tubbies_upcased
# using Symbol#to_proc
tubbies_upcased = tubbies.map(&:upcase)
p tubbies_upcased
In both cases, the output is the same:
["DIPSY", "LALA", "PO", "TINKY WINKY"]
For more info, check out these links:
- http://pragdave.pragprog.com/pragdave/2005/11/symbolto_proc.html
- http://www.dcmanges.com/blog/29
- http://memerocket.com/2007/08/02/ruby-symbolto_proc-dont-forget-it/
- http://blog.jayfields.com/2007/01/ruby-invoking-method-with.html
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